Desenvolvimento de uma nova dieta indutora de obesidade e avaliação do potencial do guaraná (Paullinia cupana) como agente terapêutico no tratamento da obesidade e síndromes associadas

A prevalência da obesidade tem aumentado drasticamente ao longo dos últimos 30 anos devido a múltiplos fatores. Além disso a obesidade tem sido considerada um dos principais fatores de risco para o desenvolvimento de diversas doenças, tornando-se um grande problema de saúde pública em todo o mundo. Há na literatura diversos tipos de dietas que induzem a obesidade, as quais são muito utilizadas para se estudar os efeitos desta desordem. A mais utilizada é a dieta hiperlipídica (do inglês high-fat diet – HFD), mas uma das mais eficientes é a chamada dieta de cafeteria (CAF), a qual é composta por alimentos altamente palatáveis, como bolachas recheadas, bolos, biscoitos salgados, queijo e carnes processadas. Estes alimentos contêm uma quantidade substancial de sal, açúcar e gordura e tem como objetivo simular a dieta ocidental humana. Porém, os componentes nutricionais e não nutricionais destes alimentos variam dependendo da região onde são adquiridos e, além disso, um animal pode escolher uma seleção diferente de alimentos do que outro, o que poderia levar animais do mesmo grupo a apresentar diferentes características patológicas. Por esse motivo, esta dieta não consegue ser replicada com precisão tornando-a muitas vezes uma má escolha para a pesquisa científica. Portanto, nós decidimos projetar uma dieta com alto teor de gordura, alto teor de açúcar, alto teor de sal e baixa teor de fibras, ou seja, mais semelhante à dieta ocidental humana, mas nutricionalmente adequada, sem aditivos e sem heterogeneidade alimentar (mistura única), a fim de reunir o melhor de ambos (HFD e CAF), tornando esta dieta mais adequada e reprodutível. Assim a proposta deste trabalho foi comparar esta dieta, nomeada de dieta ocidental, com outras duas dietas obesogênicas tradicionalmente utilizadas (HFD e CAF) em relação a eficiência na indução de obesidade e suas disfunções, bem como analisar a alteração da microbiota provocada pelas mesmas. Além disso, nós pretendemos testar se o guaraná, o qual tem sido apontado como termogênico, é capaz de impedir as disfunções induzidas pela dieta ocidental proposta por nós. Nesta tese nós mostramos que a dieta ocidental foi mais eficiente em induzir a obesidade e disfunções associadas a ela do que a HFD e a CAF. Este achado nos levou a redação de uma patente reivindicando a composição e uso desta dieta por empresas. Mostramos também que a obesidade é independente de uma severa disbiose e, portanto, devemos investigar os efeitos da obesidade sobre a microbiota a níveis mais específicos tais como gênero e espécie. Por fim demonstramos o potencial antiobesidade do guaraná e um possível mecanismo envolvido através da ativação do tecido adiposo marrom. Em conjunto, estes dois trabalhos trazem novas perspectivas para quem trabalha com obesidade, principalmente no contexto de padronização de modelos e possibilidade de novas terapias.Obesity prevalence has increased dramatically over the past 30 years due to multiple factors. In addition, obesity has been considered a major risk factor for the development of several diseases, making it a worldwide major public health problem. There are in the literature several types of diets that induce obesity, which are widely used to study the effects of this disorder. The most widely used is the high-fat diet (HFD), but one of the most efficient is the so-called cafeteria diet (CAF), which is consists of highly palatable foods such as stuffed biscuits, cakes, crackers, cheese and processed meats. These foods contain a substantial amount of salt, sugar and fat and aim to simulate the human Western diet. However, the nutritional and non-nutritional components of these foods vary depending on the region where they are purchased and, in addition, the animal may choose a different selection of foods each day that could lead to different animal characteristics of the same group. However, the nutritional and non-nutritional components of these foods vary depending on the region where they are purchased and, in addition, one animal may choose a different food selection than another, which could lead to different pathological characteristics to animals of same group. For this reason, this diet can not be replicated accurately making it often a poor choice for scientific research. Therefore, we decided to design a high-fat, high-sugar, high-salt, low-fiber diet, i.e., more similar to the western human diet, but nutritionally adequate, without additives and without food heterogeneity (unique mixture) in order to bring together the best of both (HFD and CAF), making this diet more suitable and reproducible. Thus, the proposal of this work was to compare this diet, termed Western diet, with two other traditionally used obesogenic diets (HFD and CAF) in relation to the efficiency in inducing obesity and its dysfunctions, as well as to analyse the microbiota alteration caused by them. In addition, we intend to test whether guarana, which has been designated as thermogenic, is able to prevent the dysfunctions induced by the Western diet proposed by us. In this thesis, we have shown that the Western diet was more efficient in inducing obesity and dysfunctions associated with it compared to the HFD and CAF. This finding led to the writing of a patent claiming the composition and use of this diet by companies. We also show that obesity is independent of severe dysbiosis and therefore we should investigate the effects of obesity on the microbiota at more specific levels such as gender and species. Finally, we demonstrate the potential anti-obesity of guarana and a possible mechanism involved through the activation of brown adipose tissue. Together, these two studies bring new perspectives to those who work with obesity, especially in the context of standardization of models and the possibility of new therapies

Composição indutora de obesidade em ratos e uso da composição para o preparo de uma composição para induzir obesidade em ratos

Universidade Federal do Rio Grande do SulCiências Básicas da SaúdeDepositad

Vitamin A oral supplementation induces oxidative stress and suppresses IL-10 and HSP70 in skeletal muscle of trained rats

Exercise training intensity is the major variant that influences the relationship between exercise, redox balance, and immune response. Supplement intake is a common practice for oxidative stress prevention; the effects of vitamin A (VA) on exercise training are not yet described, even though this molecule exhibits antioxidant properties. We investigated the role of VA supplementation on redox and immune responses of adult Wistar rats subjected to swimming training. Animals were divided into four groups: sedentary, sedentary + VA, exercise training, and exercise training + VA. Over eight weeks, animals were submitted to intense swimming 5 times/week and a VA daily intake of 450 retinol equivalents/day. VA impaired the total serum antioxidant capacity acquired by exercise, with no change in interleukin-1 and tumor necrosis factor- levels. In skeletal muscle, VA caused lipid peroxidation and protein damage without differences in antioxidant enzyme activities; however, Western blot analysis showed that expression of superoxide dismutase-1 was downregulated, and upregulation of superoxide dismutase-2 induced by exercise was blunted by VA. Furthermore, VA supplementation decreased anti-inflammatory interleukin-10 and heat shock protein 70 expression, important factors for positive exercise adaptations and tissue damage prevention. Our data showed that VA supplementation did not confer any antioxidative and/or protective effects, attenuating exercise-acquired benefits in the skeletal muscle

Systemic Inflammation Changes the Site of RAGE Expression from Endothelial Cells to Neurons in Different Brain Areas

The receptor for advanced glycation endproducts (RAGE) is a transmembrane, immunoglobulin-like receptor that interacts with a broad repertoire of extracellular ligands. RAGE belongs to a family of cell adhesion molecules and is considered a key receptor in the inflammation axis and a potential contributor to the neurodegeneration. The present study aimed to investigate the content and cell localization of RAGE in the brain of Wistar rats subjected to systemic inflammation induced by a single dose of lipopolysaccharide (LPS, 5 mg/kg, i.p.). Fifteen days after LPS administration, the content of RAGE was analyzed in the prefrontal cortex (PFC), hippocampus (HIPP), cerebellum (CB), and substantia nigra (SN) were investigated. RAGE levels increased in all structures, except HIPP; however, immunohistochemistry analysis demonstrated that the cell site of RAGE expression changed from blood vessel-like structures to neuronal cells in all brain areas. Besides, the highest level of RAGE expression was found in SN. Immunofluorescence analysis in SN confirmed that RAGE expression was mainly co-localized in endothelial cells (RAGE/PECAM-1 co-staining) in untreated animals, while LPS-treated animals had RAGE expression predominantly in dopaminergic neurons (RAGE/TH co-staining). Decreased TH levels, as well as increased pro-inflammatory markers (TNF-α, IL-1β, Iba-1, GFAP, and phosphorylated ERK1/2) in SN, occurred concomitantly to RAGE stimulation in the same site. These results suggest a role for RAGE in the establishment of a neuroinflammation-neurodegeneration axis that develops as a long-term response to systemic inflammation by LPS

Evaluación espaciotemporal de los efectos de estresores ambientales sobre la microbiota coralina y la salud de los arrecifes coralinos del caribe colombiano

Los arrecifes de corales son estructuras tridimensionales que producen ambientes con altísima biodiversidad. Los bienes y servidos ecosistérnlcos generados por ellos son muy diversos y pueden sumar hasta US$ 375.000 millones de dólares por año. Pero debido al calentamiento global y estresores antropogénicos locales los arrecifes están disminuyendo drásticamente en todo el mundo. Se calcula que hasta 60% de los arrecifes de corales podrían perderse hasta 2030 según estudio publicado en 2003. A nivel local, los estresores antropogénicos que más llevan a muerte de corales en la región Caribe son la escorrentía de sedimentos, la contaminación del agua, y la pesca de arrastre y dinamita. Lo más preocupante, es que se predice que estas perturbaciones aumentarán en frecuencia y gravedad durante el próximo siglo. Por su parte, algunos estudios han demostrado que la región caribe es una de las más susceptibles a dichos disturbios. Así que la comprensión de los disturbios antropogénicos será crucial para crear estrategias de conservación y revertir efectivamente la degradación de los arrecifes coralinos del Caribe colombiano. Desafortunadamente, los efectos de los disturbios antropogénicos sobre los corales han sido pobremente documentados en el sur del Caribe, donde se encuentra el Caribe colombiano. Sin embargo, esto puede estar cambiando, pues hay actualmente una conmoción mundial y local muy grande para la conservación de corales por parte da ONU, UNESCO, Colciencias y Gobierno Colombiano. En este escenario, esta investigación se enfocará a comprender los efectos de estresores antropogénicos sobre ecosistemas asociados a los corales del caribe colombiano (San Andrés, Providencia o Bahía de Cartagena) con respecto a microbiota coralina y integridad del ecosistema de los arrecifes coralinos

Targeted inhibition of RAGE in substantia nigra of rats blocks 6-OHDA-induced dopaminergic denervation

The receptor for advanced glycation endproducts (RAGE) is a pattern-recognition receptor associated with infammation in most cell types. RAGE up-regulates the expression of proinfammatory mediators and its own expression via activation of NF-kB. Recent works have proposed a role for RAGE in Parkinson’s disease (PD). In this study, we used the multimodal blocker of RAGE FPS-ZM1, which has become available recently, to selectively inhibit RAGE in the substantia nigra (SN) of rats intracranially injected with 6-hydroxydopamine (6-OHDA). FPS-ZM1 (40 μg per rat), injected concomitantly with 6-OHDA (10 μg per rat) into the SN, inhibited the increase in RAGE, activation of ERK1/2, Src and nuclear translocation of NF-kB p65 subunit in the SN. RAGE inhibition blocked glial fbrillary acidic protein and Iba-1 upregulation as well as associated astrocyte and microglia activation. Circulating cytokines in serum and CSF were also decreased by FPS-ZM1 injection. The loss of tyrosine hydroxylase and NeuN-positive neurons was signifcantly inhibited by RAGE blocking. Finally, FPS-ZM1 attenuated locomotory and exploratory defcits induced by 6-OHDA. Our results demonstrate that RAGE is an essential component in the neuroinfammation and dopaminergic denervation induced by 6-OHDA in the SN. Selective inhibition of RAGE may ofer perspectives for therapeutic approaches

High fat diet-induced obesity causes a reduction in brain tyrosine hydroxylase levels and non-motor features in rats through metabolic dysfunction, neuroinflammation and oxidative stress

Obesity is a health problem that has been associated with neuroinflammation, decreased cognitive functions and development of neurodegenerative diseases. Parkinson’s disease (PD) is a chronic neurodegenerative condition characterized by motor and non-motor abnormalities, increased brain inflammation, α-synuclein protein aggregation and dopaminergic neuron loss that is associated with decreased levels of tyrosine hydroxylase (TH) in the brain. Diet-induced obesity is a global epidemic and its role as a risk factor for PD is not clear. Herein, we showed that 25 weeks on a high-fat diet (HFD) promotes significant alterations in the nigrostriatal axis of Wistar rats. Obesity induced by HFD exposure caused a reduction in TH levels and increased TH phosphorylation at serine 40 in the ventral tegmental area. These effects were associated with insulin resistance, increased tumor necrosis factor-α levels, oxidative stress, astrogliosis and microglia activation. No difference was detected in the levels of α-synuclein. Obesity also induced impairment of locomotor activity, total mobility and anxiety-related behaviors that were identified in the open-field and light/dark tasks. There were no changes in motor coordination or memory. Together, these data suggest that the reduction of TH levels in the nigrostriatal axis occurs through an α-synuclein-independent pathway and can be attributed to brain inflammation, oxidative/nitrosative stress and metabolic disorders induced by obesit

Oral administration of carvacrol/β-cyclodextrin complex protects against 6-hydroxydopamine-induced dopaminergic denervation

Carvacrol (CARV) presents valuable biological properties such as anti-inflammatory and antioxidant activities. However, pharmacological uses of CARV are largely limited due to disadvantages related to solubility, bioavailability, preparation and storage processes. The complexation of monoterpenes with β-cyclodextrin (β-CD) increases their stability, solubility and oral bioavailability. Here, the protective effect of oral treatment with CARV/β-CD complex (25 μg/kg/day) against dopaminergic (DA) denervation induced by unilateral intranigral injection of 6-hydroxydopamine (6-OHDA - 10 μg per rat) was analyzed, in order to evaluate a putative application in the development of neuroprotective therapies for Parkinson's disease (PD). Pretreatment with CARV/β-CD for 15 days prevented the loss of DA neurons induced by 6-OHDA in adult Wistar rats. This effect may occur through CARV anti-inflammatory and antioxidant properties, as the pretreatment with CARV/β-CD inhibited the release of IL-1β and TNF-α; besides, CARV prevented the increase of mitochondrial superoxide production induced by 6-OHDA in cultured SH-SY5Y cells. Importantly, hepatotoxicity or alterations in blood cell profile were not observed with oral administration of CARV/β-CD. Therefore, this study showed a potential pharmacological application of CARV/β-CD in PD using a non-invasive route of drug delivery, i.e., oral administration

Guarana supplementation attenuated obesity, insulin resistance, and adipokines dysregulation induced by a standardized human Western diet via brown adipose tissue activation

Obesity is a metabolic disorder associated with adverse health consequences that has increased worldwide at an epidemic rate. This has encouraged many people to utilize nonprescription herbal supplements for weight loss without knowledge of their safety or efficacy. However, mounting evidence has shown that some herbal supplements used for weight loss are associated with adverse effects. Guarana seed powder is a popular nonprescription dietary herb supplement marketed for weight loss, but no study has demonstrated its efficacy or safety when administered alone. Wistar rats were fed four different diets (low‐fat diet and Western diet with or without guarana supplementation) for 18 weeks. Metabolic parameters, gut microbiota changes, and toxicity were then characterized. Guarana seed powder supplementation prevented weight gain, insulin resistance, and adipokine dysregulation induced by Western diet compared with the control diet. Guarana induced brown adipose tissue expansion, mitochondrial biogenesis, uncoupling protein‐1 overexpression, AMPK activation, and minor changes in gut microbiota. Molecular docking suggested a direct activation of AMPK by four guarana compounds tested here. We propose that brown adipose tissue activation is one of the action mechanisms involved in guarana supplementation‐ induced weight loss and that direct AMPK activation may underlie this mechanism. In summary, guarana is an attractive potential therapeutic agent to treat obesity

Obese rats are more vulnerable to inflammation, genotoxicity and oxidative stress induced by coal dust inhalation than non-obese rats

Obesity is an important nutritional disorder worldwide. Its association with environmental pollution may trigger an increase in oxidative stress and inflammatory parameters. Coal is a resource used throughout the world as an important fuel source for generating electricity. The ashes released by the coal combustion cause serious problems for human health due to their high toxicity and their capacity to bioaccumulate. The aim of this work was to investigate the effects of coal dust inhalation in the organs of obese and non-obese Wistar rats. Pro-inflammatory cytokines, oxidative stress, oxidative damage, histological analysis, comet assay, and micronuclei were investigated. Both obesity and coal dust inhalation increased the pro-inflammatory cytokines IL-1β and TNF-α and decreased HSP70 levels in serum, however, in obese animals that inhaled coal dust these changes were more pronounced. Liver histological analysis showed severe microvesicular steatosis in obese animals that inhaled coal dust. Lung histologic investigation showed abnormalities in lung structure of animals exposed to coal dust and showed severe lung distensibility in obese animals exposed to coal dust